// eslint-disable-next-line no-unused-vars
var id = 'GLOBAL'
var obj = {
    id: 'OBJ',
    a: function () {
        console.log(this.id)
    },
    b: () => {
        console.log(this.id)
    }
}
obj.a() // 'OBJ'
obj.b() // 'GLOBAL'
new obj.a() // undefined
new obj.b() // Uncaught TypeError: obj.b is not a constructor
